We, the Children
by photojourney
Summary: When Lambo's new dimension-jumping bazooka—a product of Byakuran's experimentations—goes off by accident, Mukuro decides to act nice (for once) and push Tsuna out of the line of fire. It is, quite frankly, one of the worst decisions he's ever made. (In which Mukuro plays the villain again, only to find it's much harder than he remembers it to be.) (TYL!69, TYL!100, GEN)


**Word Count: **~5,500

**Warnings:** TYL!Mukuro, TYL!Byakuran, GEN, time travel-ish, parallel-world-hopping, 69100 friendship, everyone is probably slightly OOC

**Notes:** inspired by songs by billie holiday and ella fitzgerald, because i can totally imagine mukuro listening to super sweet jazz beats

* * *

_(This man has a demon, and his demon is this.)_

_Mukuro—sixteen, nearing seventeen—awakens a second past midnight to the sound of six soft, sighing breaths instead of five._

_He stays in his position on the couch for a minute or so, blinking at the scarred ceiling and the white stars dotting the scratched windows in the corner of his eye. Then, he sits up and swings his legs around, feet kissing the nail-ridden floorboards without a sound._

_They carry him past Ken's limp form, sprawled gracelessly across his own mattress. Past Chikusa, a full hand of cards still pressed against his palm. Past M.M., faint snores reverberating within her chest, and past Flan, his face mushed against the girl's arm._

_Past Chrome, curled between her two boys with a smile playing on her lips, and—_

_He stops in front of Tsunayoshi's sleeping figure, and summons his trident._

_His knuckles bite the cold steel—a sensation that clears the remaining fog in his mind. He stares down at Tsunayoshi, at his ruffled brown hair and slender eyelashes and smooth, clean hands. Tsunayoshi, light and pure._

_Mukuro closes his eyes._

_And the hatred festering in his bones pours into his blood, and the fury hammering in his heart soars up to the heavens, and as the agony of six mutilated lifetimes in hell spreads through every thrumming vein of his being, Mukuro _smiles_. It is not beautiful. It is an ugly, wretched thing—perfectly befitting this cruel, corrupted, crumbling world._

_He doesn't let his killing intent seep past his skin. It sings inside him instead, coiled around his heart, even as he lifts his trident and poises the tips of it only a millimeter above the long stretch of Tsunayoshi's throat._

_The other teen doesn't stir._

_All it takes is a flick of the wrist._

_Mukuro knows exactly what Tsunayoshi has done to them. The unforgivable. Ken no longer reminds himself of his purpose for vengeance, and neither does Chikusa. They've gone soft, almost _feeble_, and it shows in their delighted smiles and sparkling eyes. Vongola Decimo is breaking them down, tearing them apart, and Mukuro sees the signs. He sees and knows and _seethes.

_Wrath, bitter and hateful, is the most powerful weapon of all. Xanxus knew as much._

_Tsunayoshi knows, too. The boy has already wormed his way into their defenses, destroyed the potent wrath of his subordinates, rendered them useless and pathetically vulnerable—_

_But Mukuro remembers. He remembers years of torture in the Estraneo's tender care, of dreaming through hell and waking to hell. He doesn't forget._

_It is high time for him to possess Vongola Decimo._

_Standing above the brunet, trident in hand, a tremulous rage and excitement vibrating in the tatters of his soul, he smiles. Long and slow and wide, until his cheeks burn and his teeth grit together and moisture gathers at the corners of his half-closed eyes—until dearest Chrome comes up on cat-light footsteps to embrace him from behind, and then gently, ever-so-gently guide his trident away from Tsuna's neck, starlit emotions brimming in her single violet eye._

_Mukuro lets her, but not because of any sentiment he might hold towards Sawada Tsunayoshi. Not even because he doubts his goals, or because he'll obey Chrome's wishes._

_Mukuro lets her, because—after a few moments of contemplation—he's decided he wants to see the color bleed from Tsunayoshi's horrified face before he tears his mind apart._

_(One year, two years, three years later and he still does not possess Sawada Tsunayoshi. Not now, not ever. He bows to him and laughs with him and accepts this world for the truth that it is instead of the rotting hell he once believed it to be, but—_

_All it takes is a flick of the wrist, and then—)_

* * *

It starts with a white dragon sweeping into the dining hall with the grace of a feline, a predator, unannounced and entirely unexpected.

"He-ey," Byakuran sings, and before anyone can respond, plops down on an empty seat at Tsuna's left side. He winks at them. "Long time no see, Tsuna-kun, everyone!"

Mukuro sips his cappuccino and watches as Tsuna blinks back, obviously baffled. Hayato chokes on his waffles, while Chrome smiles back and Reborn simply downs the rest of his espresso. "Byakuran? How did you even get in here?" Tsuna asks. "The doors—"

"Hah! Doors!" The dragon waves a dismissive hand. "I pulled a few tricks and snuck my way in. Your breakfast looks pretty good! Do you eat like kings every day, or is this a one-time thing? 'Cause the kitchens at our place don't make stuff like this. They should, though."

The brunet rolls his eyes. "You can have the strawberries."

"Yaaay!"

Hayato slams his hand down on the table. "Byakuran, what the hell?" he growls, more irritable than irate. This is, after all, not the first time the Millefiore boss has surprised them with an appearance. "You couldn't have bothered with telling one of our men out front, or what?"

"You're alwaysh sho mean, Gokudera-kun!" Byakuran pops the last few strawberries on Tsuna's plate into his mouth. Except—there were at least ten of those. That shouldn't be physically possible. "Where'sh the fun in tha', anyway?"

Mukuro puts his cup down on the saucer with a small clink, and spares a moment to mourn the rest of his meal. No matter how delicious the yogurt may be, he refuses to sit here and continue to listen to whatever squall the dragon has spun up this time around. While he would gladly finish his breakfast and beat in the other man's ribcage on any other date, there is still business to take care of with the Yamaguchi-gumi, meetings to attend, missions to take. His week has been a busy one, with whispers of a new intelligence network cropping up.

As if gauging the entirety of his thought process from a mere glimpse of his expression, Chrome reaches over to pat his arm. Comfort, as well as empathy. "Back for dinner?" she asks.

He chuckles and drops his tone low. "Perhaps."

"Mm, be careful."

Before he can reply with an _of course_ and an assuring statement that his work is perfectly manageable, the double doors swing open once more, and Lambo strides in. Trailing after him are two of Byakuran's Wreaths, Bluebell and Kikyo. "You really did it!" the Lightning Guardian exclaims, eyes wide and bright.

Byakuran waves at them. "Ah, hey, guys! Did I leave you behind? Sorry 'bout that!"

Immediately, Mukuro zeroes in on the large, hulking machine in Bluebell's trembling arms, cylindrical and suspiciously bazooka-like. No, it looks more like a cannon. Together with Chrome, he rises to his feet and goes around the table to join the others. "What is _that?"_ Tsuna squawks.

"It's a new bazooka I commissioned from Byakuran!" Lambo puffs up, very much like his over-inflated ego. Fifteen years old and still not a spark of intelligence inside him. "He said he'd bring over the prototype!"

Byakuran leans back and props his feet up against the table. Beside him, Hayato twitches. "Ah-ah-ah, by 'prototype', I mean the veeery first and incomplete first model. He insisted after I told him what it could do, though."

Tsuna pinches the bridge of your nose. "That's why you're here? You didn't have to lug it all the way over to the mansion, you know."

"And what can it do?" Mukuro asks, studying the sickly green lines overlapping across the silver steel exterior. Blue columns of buttons line the sides. It's certainly an upgrade from the ten-year-bazooka's design. He can allow himself some intrigue.

"Oh, well, instead of switching you with your future self, it switches you between a _really_ wide range of parallel worlds!"

"Of course it does," Hayato mutters. "Lambo…"

"D-Don't look at me like that! It sounded cool!"

Bluebell stiffens, the bulky weapon slipping in her grasp before she hoists it back up with one knee. The Rain Funeral Wreath is hardly weak—he can admit as much from personal experience—but she certainly appears that way at the moment. Her jaw is set in place, even as a small bead of sweat trickles off the backs of her arms.

Quickly, Tsuna reaches down. "Oh—sorry, Bluebell, you can give it to m—"

"No," she says. Behind her, Kikyo takes on a pained expression.

Hayato rolls his eyes. "Look, you're going to drop it and break it at this rate. Just give it to Jyuudaime or—"

"NO," Bluebell screeches.

Mukuro can't quite hold back his wince, and neither can anyone else. Her voice is akin to a banshee playing _drill sergeant_. "We'd appreciate it if you could set it on the table at least, Blue-chan," Chrome says in a mild tone.

"I can HANDLE IT," the girl snaps, glaring daggers at Lambo. "See? I can handle it JUST FINE."

Lambo leans back, hands held high. "Look, geez, it was a joke! I already know you're strong enough! Can you just put it on the table already?"

She snarls—guttural and monstrous—while heaving the bazooka onto the surface of the table, which cracks a poor plate and causes the entire room to shudder from the force of the drop.

(Somewhere in the east wing, Takeshi looks up in the middle of dressing himself and wonders why the explosions are sounding unusually early this morning.)

"As I was saying," Byakuran continues, as if a small earthquake hadn't just quaked the very floorboards of the room, "when this bazooka shoots and hits someone, that person gets switched over to a different world and the person from that world gets sent over here. It's still a work in progress, though, and—"

The crackle of breaking breakfast plates resounds through the air as the bazooka slowly inches across the table, rolling by sheer momentum. The buttons on the sides, he notes, are being crushed by the weight of it. "Ah," Byakuran says.

Hayato raises an eyebrow. "What?"

"The blue button. The trigger for the bazooka. Is that—" The dragon gets to his feet, trying to peer over the top of the machine; meanwhile, Mukuro shows considerable restraint in not pointing out that all of the buttons are blue. "Is that on the other side? It isn't, right? Because if that gets pushed down—"

The bazooka stops rolling.

Then, a small click.

The lines running across the tube glow an eerie, desert gold. Mukuro sees a distinct cyan glow from within the mouth of the bazooka, aiming straight for Tsuna's startled form, and knows what will happen in the fraction of a second before it does.

The bazooka will fire (why would you make it so easy for things to go wrong, _how_ can Byakuran be this _stupid),_ Tsuna will be caught off guard—he'll dodge, yes, but certainly not fast enough, not at such a close range.

Hayato is already reaching out, but the time he spends maneuvering himself around Mukuro's own figure will be costly. Byakuran is as well, but the chair impedes him. Mukuro is the only person standing directly next to Tsuna—thus, the only person with the power to prevent the consequences.

The only person capable of saving Neo Vongola Primo from his fate, and narrowly avoiding yet another round of chaos within the famiglia.

Well, why not?

While it would be fun to witness the havoc, Mukuro is wise enough to note that Christmas is coming up. It would be the nice thing to do—and, after all, seeing as him _doing something nice_ is a rare occasion in itself, it can be…an early present of sorts.

As a blue orb shoots out of the bazooka and hurtles towards Tsuna, Mukuro makes his decision.

(It is a conscious, deliberate decision. If his arm is already moving on instinct before he can process his thoughts and make his choice—well. Nobody needs to know.)

He pushes the brunet—hard—against the chest, with just enough force to fold Tsuna's body inward and out of the projectile's path.

And then Mukuro pulls his arm back, fully intent on avoiding the orb of light himself—and let it be said that he most certainly does _not_ entertain the idea of taking Tsuna's place as victim, since that would be both ridiculous _and_ cliché, and he's definitely not going to—

Except the orb _speeds up._

It grazes only the tip of his gloved finger, but that alone is enough. A blue light flashes, blinding him, as a tugging sensation takes over his body and the air is crushed inside his own lungs. Mukuro stumbles, the world distorting around him.

Before a myriad of dazzling colors can take over his vision, he sees Tsuna's expression—shocked—and Reborn's hand lifting upward, and Byakuran's mouth, open and calling.

And then—

* * *

Mukuro lands face-first in the middle of the ocean.

He isn't quite sure _why_ he's here (in the middle of the ocean) or _how_ this happened (he's in the _middle of the ocean)_, but the relentless force of the tide gives him little time to think much further. It tears him away from the surface, crashing and thundering with the howls of the wind.

When he finally wrestles off his coat—_damn_, that was his favorite one, there isn't a single label that can imitate the design—and manages to get his head above the waves, the first thing to escape his mouth is, not surprisingly, _"Son_ of a—"

Like a vengeful bird of prey, the water bears down on him.

Quickly, he makes a small boat using both his trident and his gloves and heaves himself onto the deck. After catching a glimpse of the incoming waves, which are impossibly _huge as fuck_, he adds turbines at the bottom. The boat rises high into the air, and Mukuro tears off the tie strangling his throat, strong winds buffeting his clothes and icing his bones rather nicely.

Why is he in the _ocean?_

His alternate self couldn't have been here. That would be ridiculous. Perhaps there was a...malfunction.

Mukuro crouches down, squinting at the horizon. Blue skies and blue seas as far as the eye can see. The breeze whips at his skin, cold and—yes, it's _freezing_, so he turns around and creates a heater at the end of the boat. It's crude and bulky, but it expels heat at full blast and chases away the urge to start shivering like some piteous little kitten.

How long has been here, now? More than five minutes, at least.

Millefiore boss or not, friend of Tsuna's or not, ally of the Vongola or not—Mukuro is going to hunt Byakuran down and _murder him._

He might as well murder Lambo, as well. The blame lies partly on his shoulders.

A coughing laugh leaves the Mist Guardian's lips as he pours glacial water out of his gloves, and wrings out half of the amount soaked into his long, loose hair. The first course of action, at this point, would be to find land. Then, find Byakuran's alternate self in this dimension. If his time in this world hasn't trickled out by then, find a way to return home.

Then, finally, after exercising his patience, rip the dragon's head off his shoulders. Unfortunately, he has no idea how long he may have to wait for the opportunity to arise.

Oh, the things he puts up with for the sake of the Vongola.

* * *

As he takes refuge in this tiny sea port—Kesennuma—and sneaks into an abandoned, run-down apartment building to dry himself off properly, Mukuro spares some time to think.

The bazooka dropped him in the Pacific Ocean next to Japan. Obviously, his parallel self wasn't there, so there must have been complications. Byakuran had said something about the machine being incomplete—which is most likely the reason why he's already spent several hours in this world, as well.

Not many differences have presented themselves between his world and this one. Kesennuma is still in its proper place, close to Rikuzentakata and somewhat Namimori. The world's leaders are the same, judging from the television screen visible through the windows of the restaurant he passed by earlier. Then again, such things would only change due to large outside influences.

After drying his clothes with his own Dying Will Flame, Mukuro pulls them on and eases himself into the rusting chair next to a sinister-looking balcony, half-unhinged. He gazes at the castles of clouds in the sky, a frown flitting across his face.

What an absurd situation to be in.

The most pressing concern, at this point, is the time he'll be spending here, and the flow of time between parallel worlds. A decade ago, during their battles with the Millefiore—who was still an enemy at the time, a week spent in the future translated to less than an hour in their present time.

How long would it take for the timer on the bazooka to tick down? How much time has he already wasted in his own world simply by sitting here for a couple of minutes?

"What're you thinking about, Mukuro-kun?"

Mukuro recognizes the voice and rises to his feet, his Mist Flames washing over the floor of the room. "I'd advise you to prepare yourself, Byakuran," he purrs—because, on second thought, the consequences are irrelevant. He'll kill the man right here, right now. "This will be far from pleasant."

On the other side of the room, Byakuran laughs, lifting his hands in the universal sign of surrender. "Ah, Mukuro-kun, I don't think—"

A magnificent crow, as large as he is tall with a snarling skull masking its face, bursts out of his back and hurtles toward the dragon, teeth and talons pointed forward—

Only to pass straight through Byakuran's body, clawing at nothing, dark wings and dark eyes caught in a frenzy as it snaps harmlessly through the Millefiore's face. He gives him a light, cheery, papery-fake smile. "You're pretty dangerous when you're angry, you know that?"

Mukuro dismisses the crow. His lips curl almost on reflex. "What is this? You're no illusion—that much I can tell."

Byakuran shrugs and flips forward into the air, wings splayed out lazily behind him. "Yep, I'm definitely real! You can call me a spirit, I guess. Or a ghost. Although I guess neither of those are really accurate, but…eh, whatever." He pulls his legs up in a criss-crossed position. "After you got hit by the bazooka, Gokudera-kun flipped out, and then Tsuna-kun told me to try to get you back and Chrome-chan got this really scary look on her face. So I used my cool Mare Ring powers to send my consciousness over to this world. No body, just plain old spirit and soul. Neat, right?"

"You couldn't have just made contact with your alternate self in this world?" Mukuro sits back down again, folding his legs rather elegantly. The dragon seems to take this as permission to approach.

"Oh, I don't think you'd want to meet that Byakuran. He's not a very friendly guy, if you get what I mean." Byakuran plows on before Mukuro can dwell on that particular piece of information. "Besides, this way it's much easier to keep an eye on you! Tsuna-kun gave me orders and all."

Mukuro barks a laugh. "Are you or are you not the boss of the Millefiore Famiglia?"

"Hey, you weren't there! Chrome-chan was all like, 'you should take responsibility for your actions, Byakuran-san,' with all her crazy killing intent unleashed, and then Kikyo and Bluebell weren't backing me up 'cause I think they're traitors and they just love Tsuna-kun more than—"

He can feel a headache blooming. "What went wrong?"

"With the bazooka?"

No, with your childhood—_yes_, the bazooka, what else could he _possibly_ be referring to?

Of course, Mukuro says none of that out loud, but Byakuran simply smiles as if reading the look on his face (and since when had he become so transparent?). "A whole lot of things, actually!" he chirps.

Mukuro aborts the movement of reaching for his weapon. It wouldn't do any good at the moment, unfortunately. "Such as?"

Byakuran holds up a finger. "For starters, the bazooka's timer is all screwed up, so nobody has any idea when you'll be sent back." Another finger. "Secondly, something must've gotten messed up along the way, so you didn't switch with your alternate self in this world." A third finger. "Also, you just happened to land yourself in one of those parallel worlds where I have no idea what's different and what's not. Congratulations!"

"How can you have no idea? You have the knowledge of every single one of your alternate selves in your grasp."

"Yeah, true, but it's really not that simply. Bluntly put, it's like I've never been here before." Byakuran shrugs. "There are some worlds I just don't really bother with, and this is one of them." He claps his hands together. "Moving on! You're probably wondering what to do at this point, right?"

Mukuro cradles his jaw in one hand and narrows his eyes. "I'm _trying_ to figure out a way to skewer you at a stake."

"That's adorable, Mukuro-kun." The dragon dares to wink at him. The urge to commit homicide soars skyward. "But really, your job right now is to just sit tight and wait for the rest of us to figure out a solution. Shoichi-kun's already working on the case. Chrome-chan's handing out your workload to the rest of the Guardians."

He chuckles, but can't quite help his fingers from curling inward. He despises the thought of relying on the others. It can't be helped, though. "Very well." A short pause. "Is that all?"

"Yup! You can explore this world in the meantime if you get too bored, I guess. I'll come by later with any updates." Byakuran waggles his fingers in some demented form of a goodbye-wave. "Tsuna-kun says to be careful, by the way!"

In a blink, the man vanishes.

Mukuro smirks. His boss should know better than to worry for him. But now…what to do, what to do? Decisions, decisions.

He sighs, and after a heartbeat or two, looks westward.

How long has it been since he last visited Namimori?

* * *

This is bizarre.

Mukuro stares down at the scene before him. Tsuna, Hayato, Takeshi, and Haru—all wearing Namimori Middle uniforms, all chattering about some banal conversation topic as they cross the street—with Reborn, still an infant, hitching a ride atop Tsuna's head.

He knows parallel worlds hold an infinite number of possibilities, but travelling back in time ten years is entirely unexpected. It's one thing to read the date off the corner of a newspaper—another thing to see the living, breathing proof before his eyes. The younger selves of his Guardians and famiglia are strolling by without a care in the world.

Crouched in the shelter of the trees, he laughs, mainly to himself. Time itself is made up of its own dimensions, after all. He should've known.

The trees barely rustle as he leaps down and moves away. There are some other people he wants to check on, as well.

Byakuran had said he never switched with his alternate self—in which case, the Rokudo Mukuro of this world is still in Vendicare. Unless something has changed in the order of events, Ken, Chikusa, and Chrome should still be in the old amusement park they once called home. That, he'd like to see.

This should be very interesting.

A wry smile crosses Mukuro's face as he lopes into Kokuyo Land's dilapidated grounds, his boots crunching against broken glass and loose dirt from the mudslides. Seven years since he last saw this place. Granted, it's not exactly his place, seeing as this is hardly his own world, but it certainly looks the same as he last remembers it to be.

Although…the 'No Pets' sign next to the far bushes to his left is still standing. From what he can recall, Ken destroyed it during one of his spats with Hayato. Perhaps it hasn't happened yet in this time, or it's simply a subtle difference between this world and his own.

Mukuro's brow furrows at the sight of the hard-packed ground above the greenhouse. This spot should be broken inward by the age-old fight between Takeshi and Ken, when Vongola Decimo had 'raided' their homeland. Had that changed as well? How curious.

He is cautious to avoid entering the buildings through any direct entrances. Even with his Mist Flames' concealment, he knows his six senses were honed and refined far before the age of sixteen. Being sensed and confronted by the children would cause a series of rippling side-effects he refuses to deal with. Instead, he weaves in and out of the shadows, flitting through the hallways of the deteriorating medical building. He peers into the room at the top floor where Chrome used to sleep, and—

He sees a boy reclining against the couch, his face lax and turned away from the doorway. With his midnight hair spiked up in the back and his dark green Kokuyo uniform, there's no doubting the presence of his younger, alternate self—alive and very, very real.

Strange.

Mukuro studies the rise and fall of the boy's chest. In this world, Vendicare did not claim him. Why is that? What could have caused such a change?

He glances around the room. A stove, a refrigerator, and the barest of essential appliances. There are no extra futons, no cards scattered across the floor. The place might as well be barren.

Each parallel world is full of an infinite number of possibilities.

Mukuro turns his gaze back to his other self, asleep and possibly dreaming.

_Think._

What if—

What if, hypothetically, Ken and Chikusa and Chrome _did not exist?_

(What then?)

* * *

Mukuro sits with his back against the wall, thoughtfully, staring down at the laptop screen with his thumb pressed gently against his mouth.

Joshima Ken and Kakimoto Chikusa aren't identified by any of the mafia's well-known databanks of this world. They were born, that much is certain, but their lives must have ended with the Estraneo's experiments. They never made it out of the laboratory.

Esashi Nagi grew up with an abusive mother and two neglectful fathers. She was hit by a truck, losing a large portion of her organs and her right eye as a result. Esashi Mariko refused to give Nagi the replacement organs she needed, leaving her to die without assistance.

(His other self, Rokudo Mukuro, survived the Estraneo and slaughtered Lancia's famiglia. He was captured by the Vindice, escaped along with a group of convicts, and tried to kill Vongola Decimo. After the subsequent failure, he was dragged back to prison—only to escape again, this time alone. Alone, and taking his place as Sawada Tsunayoshi's _sole_ Mist Guardian.)

He shuts down the networks, removes the traces of his digital presence, and stares at the codeless black screen. After a moment of rare hesitation, he turns the laptop off altogether.

They aren't his family. This Joshima and Chikusa were children when they died—only two out of many other test subjects. This Nagi never became Dokuro Chrome, never amounted to anything more than a lost, forgotten, insignificant little girl.

Isn't funny, how some things turn out to be? By chance, by fate, by consequence—

So much potential lost to this world.

Regardless, there is no point in dwelling on it. This world isn't _his._

Mukuro gets to his feet, nudging the laptop to the side—and, as the air in front of him is suddenly filled by the form and flesh of a man, summons his trident and points it forward.

Byakuran beams at him. The end of the trident disappears into his skull and comes out on the other side. "Good to see you too, Mukuro-kun!"

He chuckles, his weapon disappearing in a swirl of light. "Back so soon? And here I thought you had better things to do."

"Ouch! You wound me!" The dragon places a hand over his heart, hovering cross-legged off the ground. "But seriously, couldn't you have found a better place to stay than a broken-down hospital? I know you have some interesting tastes, but this is just beyond me. What about an apartment room? Or a warehouse, even?"

Again with the yammering. Mukuro breezes _through_ him to glance out one of the shattered window panes. Night is sliding into place. "What do you mean by 'interesting tastes'?"

"For starters, pineapples—"

"I was _sixteen."_

"Don't feel bad! I still miss your old hairstyle sometimes."

He shoves down the various methods of unconventional murder rapidly forming inside his head. "Do you bring news?"

Byakuran laughs—a loud, obnoxious sound. "Yeah, but…I don't think you're going to like it, Mukuro-kun."

He arches an eyebrow. "No?"

"Weeell, here's the thing." The other man steeples his fingers in his lap. "The reason why the bazooka switches people around between worlds—or timelines—is because a person can't exist simultaneously in two different places in the same dimension. It just doesn't work out. That's a universal law. So the system inside the bazooka always makes sure to switch you with yourself, no matter what, except—"

"That didn't happen to me."

"No, it didn't. And that's the problem. The bazooka isn't recognizing you under its system, so it can't bring you back to your original world. According to the machine working inside it, you don't actually exist. It turns out the timer really _was_ set to only five minutes, but when those five minutes passed, it couldn't locate you and drag you home."

Mukuro taps his fingers against his thigh. "Hmm, interesting." His thoughts spin inside his mind. "And how exactly do I…register myself back into this system?"

"Okay, this is the part you're not gonna like." Lazily, Byakuran's eyes bore into his own. This man has always been an excellent player. "Right now, there're two of you running around this place—Mukuro-kun, which is you, and Rokudo-kun, which is the other you." (Almost immediately, a migraine forms.) "But the bazooka only thinks there's only one of you, which is Rokudo-kun. So in order to get yourself recognized by the system, Rokudo-kun needs to be wiped off the radar entirely, so that the system can realize Mukuro-kun exists as a separate person and that he needs to be taken back to his original dimension."

Byakuran shrugs. "In other words, Rokudo-kun—your parallel self—needs to die."

Silence reigns over the room—an ancient monarch. Mukuro processes these words.

This world's version of himself—Rokudo, he might say—needs to die. Needs to be _killed_, otherwise it might take years for that boy to meet his demise. "And if he does," he says slowly, "I will be sent back to my—our—dimension."

The dragon smiles. "That's how it goes."

"To do this, I need to kill my alternate self."

"Basically."

Mukuro laughs. Brightly, cheerfully, with all his heart. How hilarious. How _amusing_. "I see. In that case, I suppose I'll have to get started right away."

"Oh?" Byakuran tips his head to the side. "It doesn't bother you? Having to kill Rokudo-kun?"

Kill this world's Rokudo Mukuro? A person who isn't him, who could never be what he is now? (Kill a monster?)

"Why would it?" he replies, an airy lilt in his voice.

This is his new mission. Kill Rokudo Mukuro.

No, it's not a problem at all.

* * *

**Endnotes:** this was written because there aren't nearly enough stories about someone other than tsuna going on cool time-travelling parallel-worldly adventures! yeah! also i really need mukuro and byakuran to become reluctant bros alright ALRIGHT

no but seriously this story sort of just _happened_ and i need to focus on faux and other business right now so please excuse me while I just kind of…stick this story here, like a sticker


End file.
